Gas operated sump pump



March 5 2. R. KANAAN 3,308,763

GAS OPERATED SUMP PUMP Filed Oct. 12, 1965 III'IIIII.

IN V/iN'l ORA United States Patent 3,308,763 GAS OPERATED SUMP PUMP Ziyad R. Kanaan, Indianapolis, Ind, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed on. 12, 1965, Ser. No. 495,203 6 Claims. (Cl. 103-87) This invention relates to a liquid metal sump pump and, more particularly, to such a pump operated by a closed circuit system utilizing an inert gas as the working fluid.

The storage and movement of liquid metal presents many problems as the liquid metal usually has high corrosive properties. Hence, it is desirable to have the least possible amount of equipment in contact with liquid metal. Liquid metals are used frequently as heat exchange materials in modern-day power plants. Thus, there is increasing need for a system to store and circulate such liquid metals.

In general, this invention relates to the use of a closedcycle pumping system utilizing an inert gas, such as argon, as the working fluid, to pump liquid metal from a reservoir. The inert gas is fed under pressure to and expanded through a turbine which drives a liquid metal pump. The inert gas is then exhausted into the liquid metal so that it bubbles therethrough, whereupon it is circulated through a vapor trap to a compressor and recycled.

It is, therefore, the object of this invention to provide a system for pumping liquid metal from a sump or reservoir utilizing the minimum amount of equipment and keeping the liquid metal insulated from external substances.

Other objects, features and advantages of the subject invention will become obvious upon reference to the following detailed description and the drawing illustrating the preferred embodiment thereof, wherein:

The figure is a schematic view of the subject invention as utilized to pump liquid metal from a reservoir.

More specifically, the figure shows a quantity of liquid metal 10 contained within an insulated tank or container 12. The tank 12 may be of any suitable type having properties designed to resist the corrosive tendencies of the liquid metal which it contains. The liquid metal 10 is fed into the tank 12 by a conduit 14 which passes through a sealed opening 16 in the tank 12.

The system for pumping the liquid metal 10 from the tank 12 includes a turbine 18 which drives a sump pump 20 which, in turn, pulls the liquid metal 10 through an inlet 22 and forces it through a conduit 24 which extends through a sealed opening 25 in the tank 12. As previously mentioned, the liquid metal, for example, may be used as a heat-exchange material whereupon the liquid metal would pass through the conduit 24 to the heatexchange devices which heat and are heated by the metal and return to the tank 12 by conduit 14.

The turbine 18 is driven by an inert gas which is con ducted to the turbine 18 through a closed conduit 26. The inert gas expands through the turbine 18 and is exhausted through conduit 28 into the liquid metal 10 and then bubbles through the liquid metal 10 into the volume 30 above the liquid metal 18 within the tank 12. The inert gas then passes through conduit 32 to a condenser or metal vapor trap 34 where any metal vapor which has become mixed with the inert gas is trapped and separated from the inert gas. This metal vapor trap 34 may be of any suitable type such as an air-oil filter in a lubrication system. Any liquid metal separated from the inert gas in the trap 34 is returned to the tank 12 through conduit 33. The inert gas is then conducted through the conduit 35 to a compressor 36 which pressurizes it and forces it into the conduit 26 through which it is delivered to the turbine 18. A throttle valve 38 is provided in the conduit 26 to modulate the flow of the inert gas to the turbine 18, thereby controlling the speed of the liquid metal pump 20. It should be noted here that any suitable inert gas, such as argon, may be used in this system. The use of an inert gas eliminates the necessity for an exhaust conduit from the turbine 18 through the liquid metal 10. This, then, reduces the amount of equipment in contact with the liquid metal 10. It should be noted that all the conduits used in this system must be of a material to suitably insulate them from the corrosive eifects of the liquid metal.

Although the operation of the subject cycle should be obvious from the above description, it will be stated briefly. The pure inert gas leaves the vapor trap 34 and is pumped by the compressor 36 through the conduit 26 to the inlet of the turbine 18. The inert gas then expands through the turbine 18 and exhausts through the conduit 28 into the liquid metal 10. The turbine 18 thus drives the liquid metal sump pump 20 which in turn forces liquid metal from the tank 12 through the conduit 24. Meanwhile, the inert gas bubbles through the liquid metal 10 and passes out of the tank 12 through the conduit 32 back to the vapor trap 34, whereupon any metal vapor is removed from the inert gas, thereby preparing the inert gas for recirculation through the system. The speed of the turbine 18 and the resulting work done by the sump pump 20 can be controlled by the throttle valve 38 which modulates the flow of the inert gas to the turbine 18.

Thus, a closed cycle pumping system is provided for the circulation of liquid metal. The sump pump 20 is selfcooling and self-lubricating as the liquid metal 10 in which it resides provides both of these functions. Another advantage of this system is that the compressor 36 does not require an after-cooler because the heat energy added by the compressor 36 to the inert gas is disposed of in the liquid metal 10.

Although the subject invention has been shown and described in detail in its preferred embodiment, it should be clear to those skilled in the art to which it pertains that many changes and modifications can be made thereto without departing from the scope of the invention.

I claim:

1. A liquid metal circulating system comprising, in combination: a closed container partially filled with liquid metal defining a gas plenum above the liquid metal, a liquid metal inlet, a pump submerged in the liquid metal, a discharge conduit from the pump to the outside of the container, a turbine submerged in the liquid metal and drivingly connected to said pump, means for delivering inert gas under pressure to said turbine, said turbine having a gas discharge outlet into the liquid metal, an inert gas outlet from said plenum, and means to recircul'ate gas from said gas outlet to said delivery means.

2. A liquid metal circulating system comprising, in combination: a closed container partially filled with liquid metal defining a gas plenum above the liquid metal, a liquid metal inlet, a pump submerged in the liquid metal, a discharge conduit from the pump to the outside of the container, a turbine submerged in the liquid metal and drivingly connected to said pump, means for delivering inert gas under pressure to said turbine, said turbine having a gas discharge outlet into the liquid metal, an inert gas outlet from said plenum, and means to recirculate gas from said gas outlet to said delivery means, including a metal vapor trap to separate liquid metal from said inert gas.

3. A liquid metal circulating system as set forth in claim 2 wherein said inert gas is argon.

4. A liquid circulating system comprising, in combination: a closed container partially filled with liquid defining a gas plenum above the liquid, a liquid inlet, a pump submerged in the liquid, a discharge conduit from the pump to the outside of the container, a turbine submerged in the liquid and drivingly connected to said pump, means for delivering inert gas under pressure to said turbine, said turbine having a gas discharge outlet into the liquid, an inert gas outlet from said plenum, and means to recirculate gas from said gas outlet to said delivery means.

5. A liquid circulating system comprising, in combina tion: a closed container partially filled with liquid defining a gas plenum above the liquid, a liquid inlet, a pump submerged in the liquid, a discharge conduit from the pump to the outside of the container, a turbine submerged in the liquid and drivingly connected to said pump, means for delivering inert gas under pressure to said turbine, said turbine having a gas discharge outlet into the liquid, an inert gas outlet from said plenum, and means to recirculate gas from said gas outlet to said delivery means including a vapor trap to separate said liquid from said inert gas.

6. A liquid circulating system as set forth in claim 5 wherein said inert gas is argon.

References Cited by the Examiner UNITED STATES PATENTS 1,739,000 12/1929 Jordao l0387 X 1,942,570 1/1934 Reed 1(l3-87 ROBERT M. WALKER, Primary Examiner. 

1. A LIQUID METAL CIRCULATING SYSTEM COMPRISING, IN COMBINATION: A CLOSED CONTAINER PARTIALLY FILLED WITH LIQUID METAL DEFINING A GAS PLENUM ABOVE THE LIQUID METAL, A LIQUID METAL INLET, A PUMP SUBMERGED IN THE LIQUID METAL, A DISCHARGE CONDUIT FROM THE PUMP TO THE OUTSIDE OF THE CONTAINER, A TURBINE SUBMERGED IN THE LIQUID METAL AND DRIVINGLY CONNECTED TO SAID PUMP, MEANS FOR DELIVERING INERT GAS UNDER PRESSURE TO SAID TURBINE, SAID TURBINE HAVING A GAS DISCHARGE OUTLET INTO THE LIQUID METAL, AN INERT GAS OUTLET FROM SAID PLENUM, AND MEANS TO RECIRCULATE GAS FROM SAID GAS OUTLET TO SAID DELIVERY MEANS. 